Cadillac 2011 DTS Owner's Manual page 115

Leaving children, helpless adults, or pets in a
vehicle with the windows closed is dangerous.
They can be overcome by the extreme heat and
suffer permanent injuries or even death from heat
stroke. Never leave a child, a helpless adult, or a
pet alone in a vehicle, especially with the windows
closed in warm or hot weather.
The vehicle aerodynamics are designed to improve fuel
economy performance. This may result in a pulsing
sound when either rear window is down and the front
windows are up. To reduce the sound, open either a
front window or the sunroof (if equipped).
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